Process for manufacturing decorative products of aluminum and alloys of aluminum

ABSTRACT

A process for manufacturing a composite sheet having a surface of anodized aluminum or alloy of aluminum having different colors in the anodized surface in which anodization is effected on a composite sheet formed of a covering sheet having surface heterogeneities of composition and a support plate having the physical and mechanical properties desired in the final product, and rolling the composite after surface treatment to effect a reduction of at least 50-fold followed by anodization.

United States Patent Sabetay PROCESS FOR MANUFACTURING DECORATIVE PRODUCTS OF ALUMINUM AND ALLOYS OF ALUMINUM Inventor: Leon Sabetay, lssoire, France Assignee: Cegedur GP, Paris, France Filed: Apr. 13, 1970 Appl No.: 28,061

Foreign Application Priority Data Apr. 16, 1969 France 69.11760 US. Cl 29/l97.5, 156/150, 204/58 Int. Cl 823p 3/00, C23b 9/02 Field of Search 204/58, 38 A, 35 N, 58;

References Cited UNITED STATES PATENTS 6/1960 Fromson 29/1975 2/1963 Daugherty, 204/58 12/1966 Daugherty 204/58 1451 Feb. 11, 1975 9/1968 Coates et all. 204/58 3.475.167 10/1969 Beatty et a1 204/58 FOREIGN PATENTS OR APPLICATIONS 1,466,294 12/1966 France 204/58 OTHER PUBLICATIONS The Surface Treatment & Finishing of A1 and its Alloys, by S. Wernick et al., 1964, pages 306-307.

Primary Examiner-R. L. Andrews [57] ABSTRACT 16 Claims, No Drawings 1 PROCESS FOR MANUFACTURING DECORATIVE PRODUCTS OF ALUMINUM AND ALLOYS OF ALUMINUM This invention relates to the manufacture of decorative products of aluminum and alloys of aluminum.

It is known that the tint of the oxide layer of an anodized aluminum or alloy of aluminum depends somewhat on the chemical composition of the metal at the surface.

This property has been used in the manufacture of decorative products having an oxide layer of various colors by anodizing the parts in which the chemical composition at the surface varies locally, depending somewhat upon the design.

Many processes are in existence for achieving local variations in chemical composition at the surface of the aluminum product. By way of example, in the case of laminated products, it is possible for two sheets of an alloy of aluminum of homogeneous chemical composition, but of a different nature, to be joined together in order to provide a composite product formed of two layers of different alloys followed by removal of one of the layers locally by etching. The etched face thus presents local variations in chemical composition whereby subsequent anodization by one of the many known anodizing processes yields different colors to the etched and non-etched portions.

In accordance with another process described in French Pat. No. 1,466,294, dated July 28, 1965, and issued to TREFIMETAUX GP of France, the surface of a sheet of aluminum is partially covered with seams welded with an alloy differing in composition from that of the sheet, after which the sheet is smoothed.

After being anodized, the welding seams appear as different colors from that of the sheet.

In accordance with a still further process, described in the previously referred to French patent, a sheet of aluminum alloy is plated with a layer of another alloy of aluminum. Thereafter, the external layer is locally heated in order to cause diffusion of the two alloys into one another with the formation of zones having different chemical compositions which develop different colors upon anodization.

The described processes are slow and expensive to carry out because they are concerned with the product near its final stage of manufacture, which is generally in the form of a thin sheet.

Furthermore, since the colors of the final outside layer, as well as other properties of the sheet, such as mechanical resistance, stability for stamping, etc., depend primarily on the chemical composition of the composite, this may result in conflict between the desired colors and the desired properties of the final product.

lt is an object of this invention to produce and to provide a method for producing composite sheets having surface designs of local chemical heterogeneities whereby the inconveniences heretofore described can be overcome for producing colors which differ in the surface of the metal.

ln accordance with the practice of this invention, use is made of a composite sheet, known as a covering sheet, which is relatively thin and has on the surface zones of various chemical compositions corresponding to the tints desired in the final oxide layer.

The sheet is joined, as by welding or by hot rolling, with the heterogeneous phase outermost onto a relatively thick plate, hereinafter referred to as the support plate, the chemical composition of the support plate corresponding to the mechanical or physical properties desired for the final product and in which the ratio of thickness between the support and the cover sheet is at least equal to 5. The assembly, comprising the support plate and cover sheet joined one to the other, is then rolled to the desired final thickness, which should be at most equal to H15 and preferably in the range of l/30 to H500 of the initial thickness.

In this way, an elongate strip formed of the composite sheet is obtained which has designs on the surface in the form of elongated veins, of which the chemical compositions can vary progressively from one vein to the other and which are capable of producing, by anodization, a decorative design with tint variations in which the overall appearance is reproduced throughout the length of the strip.

This possibility for reproducing the overall appearance of the design along the strip represents a marked aesthetic improvement. When a strip is cut into segments of smaller dimension, such as comparable to the sheets obtained by the practices of the prior art, and when assembled in side-by-side relationship and/or in end-to-end relationship in order to decorate a wall, such as a building facade, the segments are not different one from the other.

Since the support plate is much thicker than the cover sheet, the mechanical properties of the composite will correspond to those of a simple sheet formed solely of the support plate.

Depending on the nature of the support, the composite sheet can, for example, be subjected to a mechani cal forming treatment and/or to a heat treatment which may be adapted to impart high mechanical characteristics. In accordance with a preferred embodiment of the invention, the cover sheet is selected to have a thickness within the range of a few millimeters to several tens of millimeters, such as up to millimeters, before application while the support has a thickness which may be within the range of 6 to 20 times the thickness of the cover sheet.

Because of the possibility of being able simultaneously to select the process for manufacturing the cover sheet, the position of the alloys constituting the composite product, the ratio between the thickness of the support and cover sheet, and also the final anodization process, it is possible to provide for infinite variations in the aesthetic and physical and mechanical properties of the composite product of this invention.

The following example is given by way of illustration, and not by way of limitation, of the practice of this invention:

It is desired to manufacture, by the practice of this invention, a composite sheet consisting of an alloy of aluminum having thin veins of light metallic appearance alternating with larger veins of a deep grey appearance.

For manufacturing the cover sheet, use is made of a sheet having a thickness of 20 millimeters, a length of 3 meters and a width of 1.5 meters, formed of an A-Ml alloy containing approximately 1.2 percent by weight manganese and 98.8 percent by weight of aluminum with the usual impurities. One face of the sheet is plated beforehand with a layer having a thickness of 2 millimeters of A-Sl2 alloy containing about 12 percent by weight silicon and 88 percent by weight aluminum, plus impurities.

The surface layer of A-Sl2 alloy and the underlying layer of A-Ml alloy are locally melted in accordance with a design in the form of zig-zag lines, as by the use of a torch or an arc welding head of the known TlG type. In the melted zone, the two alloys A-Sl2 and A-Ml become partially intermixed in a more or less regular manner. In the adjacent unmelted portions, the two alloys A-Sl2 and A-Ml mutually diffuse in the solid state one into another.

This cover sheet is then plated by hot rolling onto a support having a thickness of 200 millimeters, a length of 3 meters and a width of 1.5 meters. The support consists of A-MIG alloy containing about 1.3 percent by weight manganese, 1.1 percent by weight magnesium and 97.6 percent by weight aluminum plus impurities. The cover sheet is positioned with the surface of A-S l 2 facing outwardly.

Thereafter, the assembly comprising the support and cover sheet is rolled to a thickness of about 4 millimeters. The original motif of heterogeneities in the cover sheet will be extended more than 50-fold.

The composite strip, having a thickness of 4 millimeters, is subjected to surface pickling to a depth of about 2/l00 millimeters, followed by anodization in an aqueous sulphuric acid solution, in accordance with known procedures. The anodized strip has a deep grey surface decorated with more or less elongated light veins, suggesting the appearance of the surface of certain natural rocks.

When this composite product is used for decorating shop fronts or walls, a remarkable aesthetic effect is ohtainetl.

The composite product of this invention can he employed in such fields as architecture, furniture, household articles, automobile bodies and various articles for decorative and/or structural purposes.

I claim:

1. A process for manufacturing composite sheets including a face sheet of aluminum or an alloy of aluminum having on the surface local chemical heterogeneities capable of causing variation in tint in response to anodization comprising positioning a relatively thin composite sheet having local surface heterogeneities of a composition corresponding to the tints desired for the final anodized oxide layer to cover the entire surface of a relatively thick support plate consisting of a metal having the mechanical and/or physical properties desired for the final product, the ratio between the thickness of the support and the composite sheet being at least equal to 5, rolling the composite sheet and support for reduction in combined thickness by an amount at least equal to l/l5 of the initial thickness.

2. The process as claimed in claim 1 in which the composite sheet is formed of two layers of different alloys of aluminum.

3. The process as claimed in claim 2 in which the two layers are locally melted in predetermined patterns.

4. The process as claimed in claim 3 in which local melting is effected by means of a torch.

5. The process as claimed in claim 3 in which local melting is effected by means of arc welding.

6. The process as claimed in claim 2 in which the composite sheet is formed with one layer of an alloy of aluminum containing approximately 12 percent by weight silicon with the remainder aluminum plus impurities and another layer of an alloy of aluminum containing approximately 1.2 percent by weight manganese with the remainder aluminum plus impurities.

7. The process as claimed in claim 6 in which the layer of alloy of'aluminum containing the silicon is plated onto the other layer.

8. The process as claimed in claim 1 which includes the step of anodizing the composite rolled sheet for development of different colors in the various patterns on the surface of the sheet.

9. A decorative product produced by the method of claim 8.

10. The process as claimed in claim 1 in which the support plate is aluminum or an alloy of aluminum.

1]. The process as claimed in claim 1 in which the composite sheet is fixed onto the support plate by weldmg.

[2. The process as claimed in claim I in which the composite sheet is fixed onto the support plate by hot rolling.

13. The process as claimed in claim 1 in which the composite sheet has a thickness within the range of a few millimeters to several tens of millimeters.

14. The process as claimed in claim 1 in which the ratio between the thickness of the support plate and the composite sheet is within the range of 6 to 20.

15. The process as claimed in claim 1 in which the final thickness after rolling the assembly of the composite sheet and support is within the range of H30 to H500 of the initial thickness.

16. A decorative product obtained by anodizing the composite sheet ma nufactufed the process of claim 1. 

1. A PROCESS FOR MANUFACTURING COMPOSITE SHEETS INCLUDING A FACE SHEET OF ALUMINUM OR AN ALLOY OF ALUMINUM HAVING ON THE SURFACE LOCAL CHEMICAL HETEROGENEITES CAPABLE OF CAUSING VARIATION IN TINT IN RESPONSE TO ANODIZATION COMPRISING POSITIONING A RELATIVELY THIN COMPOSITE SHEET HAVING LOCAL SURFACE HETEROGENEITIES OF A COMPOSITION CORRESPONDING TO THE TINTS DESIRED FOR THE FINAL ANODIZED OXIDE LAYER TO COVER THE ENTIRE SURFACE OF A RELATIVELY THICK SUPPORT PLATE CONSISTING OF A METAL HAVING THE MECHANICAL AND/OR PHYSICAL PROPERTIES DESIRED FOR THE FINAL PRODUCT, THE RATIO BETWEEN THE THICKNESS OF THE SUPPORT AND THE COMPOSITE SHEET BEING AT LEAST EQUAL TO 5, ROLLING THE COMPOSITE SHEET AND SUPPORT FOR REDUCTION IN COMBINED THICKNESS BY AN AMOUNT AT LEAST EQUAL TO 1/15 OF THE INITIAL THICKNESS.
 2. The process as claimed in claim 1 in which the composite sheet is formed of two layers of different alloys of aluminum.
 3. The process as claimed in claim 2 in which the two layers are locally melted in predetermined patterns.
 4. The process as claimed in claim 3 in which local melting is effected by means of a torch.
 5. The process as claimed in claim 3 in which local melting is effected by means of arc welding.
 6. The process as claimed in claim 2 in which the composite sheet is formed with one layer of an alloy of aluminum containing approximately 12 percent by weight silicon with the remainder aluminum plus impurities and another layer of an alloy of aluminum containing approximately 1.2 percent by weight manganese with the remainder aluminum plus impurities.
 7. The process as claimed in claim 6 in which the layer of alloy of aluminum containing the silicon is plated onto the other layer.
 8. The process as claimed in claim 1 which includes the step of anodizing the composite rolled sheet for development of different colors in the various patterns on the surface of the sheet.
 9. A decorative product produced by the method of claim
 8. 10. The process as claimed in claim 1 in which the support plate is aluminum or an alloy of aluminum.
 11. The process As claimed in claim 1 in which the composite sheet is fixed onto the support plate by welding.
 12. The process as claimed in claim 1 in which the composite sheet is fixed onto the support plate by hot rolling.
 13. The process as claimed in claim 1 in which the composite sheet has a thickness within the range of a few millimeters to several tens of millimeters.
 14. The process as claimed in claim 1 in which the ratio between the thickness of the support plate and the composite sheet is within the range of 6 to
 20. 15. The process as claimed in claim 1 in which the final thickness after rolling the assembly of the composite sheet and support is within the range of 1/30 to 1/500 of the initial thickness.
 16. A decorataive product obtained by anodizing the composite sheet manufactured by the process of claim
 1. 